There has been known a dry multi-disc clutch that is arranged in the midst of the transmission of power from a crankshaft to wheels for transmitting the power or cutting off the transmission of the power (see Japanese Patent Publication 2864396 (page 6, FIG. 3), for example).
FIG. 3 of the above-mentioned publication is reproduced here and the above-mentioned technique is explained in conjunction with the drawing. However, symbols described in the publication are renumbered and names of parts described in the publication are partially changed.
FIG. 11 is a reproduced drawing of FIG. 3 of the Japanese Patent Publication 2864396. A dry multi-disc clutch 220 is a clutch which is substantially constituted of a primary gear 222 which transmits power of a crankshaft 221, a clutch outer 223 which is in a spline engagement with the primary gear 222, a plurality of drive-side friction discs 224 which are engaged with the clutch outer 223, driven-side friction discs 225 which are alternately overlapped to these drive-side friction discs 224, a clutch center 226 with which the driven-side friction discs 225 are engaged, a main shaft 227 which is mounted on the clutch center 226, and a pressure plate 228 which enables the transmission of power from the clutch outer 223 to the clutch center 226 by pushing the drive-side friction discs 224 and the driven-side friction discs 225.
However, in the above-mentioned dry multi-disc clutch 220, the friction heat which is generated when the drive-side friction discs 224 and the driven-side friction discs 225 are made to push each other using the pressure plate 228 and the heat transmitted from the engine (not shown in the drawing) are liable to be accumulated in the inside of the dry multi-disc clutch 220. That is, a technique that can efficiently radiate the friction heat generated by the dry multi-disc clutch 220 and the heat transmitted from the engine is required.
Further, it is also desirable to sequentially discharge wear powder which is generated from the drive-side friction discs 224, the driven-side friction discs 225 and the like when the drive-side friction discs 224 and the driven-side friction discs 225 are pushed by the pressure plate 228 to the outside.
Accordingly, it is an object of the present invention to provide a dry multi-disc clutch which can efficiently radiate the friction heat generated in the inside of the clutch and the heat transmitted from an engine and, at the same time, can discharge wear power which is generated in the inside of the clutch.